Maintaining blood glucose levels

Insulin, a hormone produced by the pancreas, acts to maintain blood glucose levels within normal limits (60-120 mg/dL). This is accomplished by die release of small amounts of insulin into die bloodstream tiirough-out the day in response to changes in blood glucose levels. Insulin is essential for die utilization of glucose in cellular metabolism and for die proper metabolism of protein and fat. 

Gluconeogenesis makes glucose from pyruvate to help maintain blood glucose levels. 

Protein phosphorylation in response to rising cAMP levels activates enzymes involved in maintaining blood glucose levels and in making ATP. 

The liver maintains blood glucose levels, makes fat, makes ketone bodies, and stores glycogen. 

Pancreatic Hormones Play a Major Role in Maintaining Blood Glucose Levels Hormones Are Major Vehicles for Intercellular Communication... 

Glycogen is stored mainly by the liver and skeletal muscle as an energy reserve. The role of stored glycogen in muscle is to provide a source of energy upon prolonged muscle contraction. In contrast, glycogen stored in the liver is used to maintain blood glucose levels. 

Glucagon has the function of maintaining blood glucose levels, because certain tissues, such as brain and red blood cells, depend heavily on glucose for... 

Low-carbohydrate diets restrictthe intake of carbohydrates, sometimes resulting in rapid weight loss. The weight is lost because glycogen and fatty acids are burned to maintain blood glucose levels. 

The liver has the major responsibility for maintaining blood glucose levels. Glucose is required particularly by tissues such as the brain and red blood cells. The brain oxidizes glucose to C02 and H20, and red blood cells oxidize glucose to pyruvate and lactate. 

Within the first few hours of fasting, glycogenolysis is primarily responsible for maintaining blood glucose levels. 

A) cannot maintain blood glucose levels either by glycogenolysis or by gluconeogenesis... 

Glycogen is not as reduced as fatty acids are and consequently not as energy rich. Why isn t all excess fuel stored as fatty acids rather than as glycogen The controlled release of glucose from glycogen maintains blood-glucose levels between meals. The circulating blood keeps the brain supplied... 

The answer is d. (Murray, pp 505-626. Scriver, pp 4029-4240. Sack, pp 121-138. Wilson, pp 287-320.) Although the liver is the major site of the formation of free glucose to maintain blood glucose levels, the kidneys and intestinal epithelium (e.g., duodenum, jejunum, and ileum) may also release glucose. All of these tissues contain the enzyme glucose-6-phosphatase, an endoplasmic reticulum enzyme that dephosphorylates glucose and allows it to be transferred out of the cells. No other tissues in mammals contain this enzyme. 

---